1. Field of the Invention
The present invention relates to a mounting structure of drivers cab to base frame in construction machine such as hydraulic excavator.
2. Description of the Related Art
As for a construction machine equipped with a drivers cab on a base frame, for example, there is a hydraulic excavator wherein an operator's cab is connected to a rotating frame through a vibration-proof mount, as disclosed in Japanese Patent Laid-Open No. 2001-193103 (Patent Document 1). FIG. 14 is an enlarged side sectional view showing a part of the hydraulic excavator of Patent Document 1.
As shown in FIG. 14, a vibration-proof mount 101 is provided with a threaded rod 105 extending above from a mount main body 104 fixed to a beam 103 of a rotating frame 102. The threaded rod 105 expands and contracts with respect to the mount main body 104, thereby exhibiting a vibration-proof function.
The threaded rod 105 is tightened by a nut 108 from above in a state of being passed through a floor plate 107 of an operator's cab positioned on the mount main body 104. As a result of connecting the threaded rod 105 and the floor plate 107, the operator's cab is supported on the rotating frame 102. Therefore, the vibration-proof function by the expansion and contraction of the threaded rod 105 is exerted when the floor plate 107 and the mount main body 104 are relatively displaced up and down.
Further, in the hydraulic excavator in Patent Document 1, a bolt 109 for regulating a further lift of the operator's cab at the time of exceeding the normal stroke of the vibration-proof mount 101 is provided. A lower end part of the bolt 109 is fixed to the beam 103 in a state of being passed through the beam 103 vertically, and a nut 110 is mounted to an upper end part thereof in a state where the bolt 109 is passed through the floor plate 107 vertically. The nut 110 is arranged with a gap 111 between the floor plate 107 so as to function as a coming-off prevention of the bolt 109 with respect to the floor plate 107 when the floor plate 107 and the rotating frame 102 are spaced by a predetermined distance. That is, when the floor plate 107 is spaced more than the gap 111, the floor plate 107 and the nut 110 are in contact with each other and the movement of the floor plate 107 is regulated by means of the nut 110.
However, in Patent Document 1, the floor plate 107 and the nut 110 are made in contact with each other in order to regulate the lift of operator's cab, and therefore there is a need for setting the strength of the floor plate 107 higher than the normal. Specifically, the configuration in which a reinforcing plate 112 is provided at the floor plate 107 to reinforce the floor plate 107 is disclosed.